summaryrefslogtreecommitdiff
path: root/docs/CommandGuide/llvm-bcanalyzer.pod
diff options
context:
space:
mode:
Diffstat (limited to 'docs/CommandGuide/llvm-bcanalyzer.pod')
-rw-r--r--docs/CommandGuide/llvm-bcanalyzer.pod315
1 files changed, 315 insertions, 0 deletions
diff --git a/docs/CommandGuide/llvm-bcanalyzer.pod b/docs/CommandGuide/llvm-bcanalyzer.pod
new file mode 100644
index 0000000000..b0bc0cddba
--- /dev/null
+++ b/docs/CommandGuide/llvm-bcanalyzer.pod
@@ -0,0 +1,315 @@
+=pod
+
+=head1 NAME
+
+llvm-bcanalyzer - LLVM bitcode analyzer
+
+=head1 SYNOPSIS
+
+B<llvm-bcanalyzer> [I<options>] [F<filename>]
+
+=head1 DESCRIPTION
+
+The B<llvm-bcanalyzer> command is a small utility for analyzing bitcode files.
+The tool reads a bitcode file (such as generated with the B<llvm-as> tool) and
+produces a statistical report on the contents of the bitcode file. The tool
+can also dump a low level but human readable version of the bitcode file.
+This tool is probably not of much interest or utility except for those working
+directly with the bitcode file format. Most LLVM users can just ignore
+this tool.
+
+If F<filename> is omitted or is C<->, then B<llvm-bcanalyzer> reads its input
+from standard input. This is useful for combining the tool into a pipeline.
+Output is written to the standard output.
+
+=head1 OPTIONS
+
+=over
+
+=item B<-nodetails>
+
+Causes B<llvm-bcanalyzer> to abbreviate its output by writing out only a module
+level summary. The details for individual functions are not displayed.
+
+=item B<-dump>
+
+Causes B<llvm-bcanalyzer> to dump the bitcode in a human readable format. This
+format is significantly different from LLVM assembly and provides details about
+the encoding of the bitcode file.
+
+=item B<-verify>
+
+Causes B<llvm-bcanalyzer> to verify the module produced by reading the
+bitcode. This ensures that the statistics generated are based on a consistent
+module.
+
+=item B<-help>
+
+Print a summary of command line options.
+
+=back
+
+=head1 EXIT STATUS
+
+If B<llvm-bcanalyzer> succeeds, it will exit with 0. Otherwise, if an error
+occurs, it will exit with a non-zero value, usually 1.
+
+=head1 SUMMARY OUTPUT DEFINITIONS
+
+The following items are always printed by llvm-bcanalyzer. They comprize the
+summary output.
+
+=over
+
+=item B<Bitcode Analysis Of Module>
+
+This just provides the name of the module for which bitcode analysis is being
+generated.
+
+=item B<Bitcode Version Number>
+
+The bitcode version (not LLVM version) of the file read by the analyzer.
+
+=item B<File Size>
+
+The size, in bytes, of the entire bitcode file.
+
+=item B<Module Bytes>
+
+The size, in bytes, of the module block. Percentage is relative to File Size.
+
+=item B<Function Bytes>
+
+The size, in bytes, of all the function blocks. Percentage is relative to File
+Size.
+
+=item B<Global Types Bytes>
+
+The size, in bytes, of the Global Types Pool. Percentage is relative to File
+Size. This is the size of the definitions of all types in the bitcode file.
+
+=item B<Constant Pool Bytes>
+
+The size, in bytes, of the Constant Pool Blocks Percentage is relative to File
+Size.
+
+=item B<Module Globals Bytes>
+
+Ths size, in bytes, of the Global Variable Definitions and their initializers.
+Percentage is relative to File Size.
+
+=item B<Instruction List Bytes>
+
+The size, in bytes, of all the instruction lists in all the functions.
+Percentage is relative to File Size. Note that this value is also included in
+the Function Bytes.
+
+=item B<Compaction Table Bytes>
+
+The size, in bytes, of all the compaction tables in all the functions.
+Percentage is relative to File Size. Note that this value is also included in
+the Function Bytes.
+
+=item B<Symbol Table Bytes>
+
+The size, in bytes, of all the symbol tables in all the functions. Percentage is
+relative to File Size. Note that this value is also included in the Function
+Bytes.
+
+=item B<Dependent Libraries Bytes>
+
+The size, in bytes, of the list of dependent libraries in the module. Percentage
+is relative to File Size. Note that this value is also included in the Module
+Global Bytes.
+
+=item B<Number Of Bitcode Blocks>
+
+The total number of blocks of any kind in the bitcode file.
+
+=item B<Number Of Functions>
+
+The total number of function definitions in the bitcode file.
+
+=item B<Number Of Types>
+
+The total number of types defined in the Global Types Pool.
+
+=item B<Number Of Constants>
+
+The total number of constants (of any type) defined in the Constant Pool.
+
+=item B<Number Of Basic Blocks>
+
+The total number of basic blocks defined in all functions in the bitcode file.
+
+=item B<Number Of Instructions>
+
+The total number of instructions defined in all functions in the bitcode file.
+
+=item B<Number Of Long Instructions>
+
+The total number of long instructions defined in all functions in the bitcode
+file. Long instructions are those taking greater than 4 bytes. Typically long
+instructions are GetElementPtr with several indices, PHI nodes, and calls to
+functions with large numbers of arguments.
+
+=item B<Number Of Operands>
+
+The total number of operands used in all instructions in the bitcode file.
+
+=item B<Number Of Compaction Tables>
+
+The total number of compaction tables in all functions in the bitcode file.
+
+=item B<Number Of Symbol Tables>
+
+The total number of symbol tables in all functions in the bitcode file.
+
+=item B<Number Of Dependent Libs>
+
+The total number of dependent libraries found in the bitcode file.
+
+=item B<Total Instruction Size>
+
+The total size of the instructions in all functions in the bitcode file.
+
+=item B<Average Instruction Size>
+
+The average number of bytes per instruction across all functions in the bitcode
+file. This value is computed by dividing Total Instruction Size by Number Of
+Instructions.
+
+=item B<Maximum Type Slot Number>
+
+The maximum value used for a type's slot number. Larger slot number values take
+more bytes to encode.
+
+=item B<Maximum Value Slot Number>
+
+The maximum value used for a value's slot number. Larger slot number values take
+more bytes to encode.
+
+=item B<Bytes Per Value>
+
+The average size of a Value definition (of any type). This is computed by
+dividing File Size by the total number of values of any type.
+
+=item B<Bytes Per Global>
+
+The average size of a global definition (constants and global variables).
+
+=item B<Bytes Per Function>
+
+The average number of bytes per function definition. This is computed by
+dividing Function Bytes by Number Of Functions.
+
+=item B<# of VBR 32-bit Integers>
+
+The total number of 32-bit integers encoded using the Variable Bit Rate
+encoding scheme.
+
+=item B<# of VBR 64-bit Integers>
+
+The total number of 64-bit integers encoded using the Variable Bit Rate encoding
+scheme.
+
+=item B<# of VBR Compressed Bytes>
+
+The total number of bytes consumed by the 32-bit and 64-bit integers that use
+the Variable Bit Rate encoding scheme.
+
+=item B<# of VBR Expanded Bytes>
+
+The total number of bytes that would have been consumed by the 32-bit and 64-bit
+integers had they not been compressed with the Variable Bit Rage encoding
+scheme.
+
+=item B<Bytes Saved With VBR>
+
+The total number of bytes saved by using the Variable Bit Rate encoding scheme.
+The percentage is relative to # of VBR Expanded Bytes.
+
+=back
+
+=head1 DETAILED OUTPUT DEFINITIONS
+
+The following definitions occur only if the -nodetails option was not given.
+The detailed output provides additional information on a per-function basis.
+
+=over
+
+=item B<Type>
+
+The type signature of the function.
+
+=item B<Byte Size>
+
+The total number of bytes in the function's block.
+
+=item B<Basic Blocks>
+
+The number of basic blocks defined by the function.
+
+=item B<Instructions>
+
+The number of instructions defined by the function.
+
+=item B<Long Instructions>
+
+The number of instructions using the long instruction format in the function.
+
+=item B<Operands>
+
+The number of operands used by all instructions in the function.
+
+=item B<Instruction Size>
+
+The number of bytes consumed by instructions in the function.
+
+=item B<Average Instruction Size>
+
+The average number of bytes consumed by the instructions in the funtion. This
+value is computed by dividing Instruction Size by Instructions.
+
+=item B<Bytes Per Instruction>
+
+The average number of bytes used by the function per instruction. This value is
+computed by dividing Byte Size by Instructions. Note that this is not the same
+as Average Instruction Size. It computes a number relative to the total function
+size not just the size of the instruction list.
+
+=item B<Number of VBR 32-bit Integers>
+
+The total number of 32-bit integers found in this function (for any use).
+
+=item B<Number of VBR 64-bit Integers>
+
+The total number of 64-bit integers found in this function (for any use).
+
+=item B<Number of VBR Compressed Bytes>
+
+The total number of bytes in this function consumed by the 32-bit and 64-bit
+integers that use the Variable Bit Rate encoding scheme.
+
+=item B<Number of VBR Expanded Bytes>
+
+The total number of bytes in this function that would have been consumed by
+the 32-bit and 64-bit integers had they not been compressed with the Variable
+Bit Rate encoding scheme.
+
+=item B<Bytes Saved With VBR>
+
+The total number of bytes saved in this function by using the Variable Bit
+Rate encoding scheme. The percentage is relative to # of VBR Expanded Bytes.
+
+=back
+
+=head1 SEE ALSO
+
+L<llvm-dis|llvm-dis>, L<http://llvm.org/docs/BitCodeFormat.html>
+
+=head1 AUTHORS
+
+Maintained by the LLVM Team (L<http://llvm.org>).
+
+=cut